Silene dioica (Red Campion)

We are getting spoilt for choice as the year progresses and more plants come into flower. After much umming and ahhing I have decided on Silene dioica (Red Campion), a member of the large Caryophyllaceae (Pink Family). Besides being an attractive plant of generally shady places, it is unusual in being dioecious. This means that the flowers are unisexual (either male or female) and are found on separate plants. So the flowers on a particular plant are either all male or all female.

To tell which is which you need to have a close look to see if the ten anthers are visible (male plant), or peel the flower in half to see the five styles (female plant) . Alternatively you can give the base of the flower a gentle squeeze. If it’s female you can feel the hard ovary within; in the males there is no resistance and the flower collapses between your finger and thumb.

This is the ultimate way to ensure that self-fertilisation doesn’t happen: pollen must come from another plant, ensuring cross-fertilisation and greater mixing of genes. This in turn will lead to greater genetic diversity within the population. Greater genetic diversity means increased likelihood of survival through the vicissitudes of natural selection. Dioecious plants are more likely to form hybrids than monoecious plants. No scent is produced and flowers are pollinated by a variety of insects, from bees to moths and flies.

Native. Sx: very common. Woodland clearings and rides; hedgerows and roadside banks; maritime cliffs and scrub. Widespread, usually in slightly damp shady habitats.

Source: S. dioica (L.) Clairv. Red Campion, The Flora of Sussex (2018)

The plant has many folklore names and associations, being known variously as the plant of snake, devil, goblin and death. Seems somewhat extreme but it used to be said that if you picked its flowers your father would die. This was in contrast to picking the flowers of its close relative, Silene latifolia (White Campion), which would result in your mother’s death. Other myths involve death by thunder and lightning.

S. dioica is native, whereas S. latifolia is an archaeophyte. The former is a perennial whereas the latter can behave like an annual. The distribution of the latter is markedly different to that of S. dioica (see map) but where they grow together hybridisation can occur resulting in a plant that is fertile, often vigorous, and perennial. It is known as Silene x hampeana. When it occurs it can become the dominant plant in the area. There aren’t that many records in Sussex so it is worth looking out for. The difficulty lies in its identification based on intermediate characteristics (mainly light pink flowers and a fruit capsule intermediate between that of the parents) when there is a great deal of variation in the appearance of S. dioica itself. The hybrid itself is also dioecious.

Albinism can occur in S. dioica, producing plants that superficially resemble S. latifolia. These are in fact easy to discern as they lack any anthocyanin, thus lacking the red-purple colouration of the stems and calyces. Silene is a large genus in the UK, with 17 species recorded in Sussex. My particular favourite is S. flos-cuculi (Ragged Robin), and not just because of its name.